February 2023 - vsnet-chat - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-chat 9326] GDS J1145134-620057: IW And
by Taichi Kato 25 Feb '23

25 Feb '23

GDS J1145134-620057: IW And ATLAS: 15.8-18.2. IW And behavior in early 2023. Some hint in 2022.

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[vsnet-chat 9325] GDS J1308184-633131: IW And
by Taichi Kato 25 Feb '23

25 Feb '23

GDS J1308184-633131: IW And ATLAS: 15.6-18.6. Long standstill + at least one terminal brightening.

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[vsnet-chat 9324] GDS J1010438-582025: active dwarf nova
by Taichi Kato 25 Feb '23

25 Feb '23

GDS J1010438-582025: active dwarf nova ATLAS: 14.8-18.4. Frequent outbursts. SS Cyg? (Some outbursts resembles superoutbursts, but look like long outbursts of an SS Cyg star)

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[vsnet-chat 9323] GDSJ0703457-063947: IW And star
by Taichi Kato 25 Feb '23

25 Feb '23

GDSJ0703457-063947: IW And star Using ATLAS forced photometry (Tonry et al. 2018; Shingles et al. 2021), this object turned out to be an IW And star (typical behavior in 2022). The variation was more heartbeat-like in 2020-2021, when the object was slightly brighter. This may be a suggestion of various IW And-type behavior depending on the mass-transfer rate.

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[vsnet-chat 9322] MV Leo: unusual start of standstill
by Taichi Kato 24 Feb '23

24 Feb '23

MV Leo: unusual start of standstill Using ATLAS and ZTF data, I found that this object entered a standstill almost directly from a low state in 2020 Mar.-Apr. Such behavior is unexpected. This standstill ended with an outburst like an IW And star.

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[vsnet-chat 9321] 6dFg0002074-374917: deeply eclpsing likely SU UMa star
by Taichi Kato 24 Feb '23

24 Feb '23

6dFg0002074-374917: deeply eclpsing likely SU UMa star Using ATLAS forced photometry (Tonry et al. 2018; Shingles et al. 2021). Porb=0.0711838(1) d. 1.5-mag deep eclipses and orbital humps in quiescence. Likely superoutburst in 2020.

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[vsnet-chat 9320] VSOLJ Variable star bulletin No.111
by meineko 23 Feb '23

23 Feb '23

VSOLJ Variable star bulletin No.111 is now available at http://vsolj.cetus-net.org/bulletin.html No.111 2023 Feb. MGAB-V240: 23-min AM CVn star showing both 12-d supercycle and standstills Taichi Kato Seiichiro Kiyota VSOLJ

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[vsnet-chat 9319] VSOLJ Variable Star Bulletin No.109 and No.110
by meineko 20 Feb '23

20 Feb '23

Following isues of VSOLJ Variable Star Bulletin are available at http://vsolj.cetus-net.org/bulletin.html No.109 2023 Feb. ASASSN-15cm: an SU UMa star with an orbital period of 5.0 hours Taichi Kato No.110 2023 Feb. On the orbital period of the dwarf nova CW Mon Taichi Kato and Franz-Josef Hambsch Seiichiro Kiyota VSOLJ

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[vsnet-chat 9318] Re: MGAB-V240: standstill interrupted by fading (AM CVn?)
by Taichi Kato 20 Feb '23

20 Feb '23

Re: MGAB-V240: standstill interrupted by fading (AM CVn?) > If this identification is correct, repeated regular > outbursts before 2020 were superoutbursts (with a supercycle > of about 10-15 d). Faint, but unusual object. I indeed detected superhumps during one of its outburst in 2018 June-July (time-resolved ZTF data on two nights). The period was 0.015822(9) d and an amplitude of 0.09 mag. This object is probably between dwarf nova-type CR Boo (Porb=0.017029 d) and novalike HP Lib (Porb=0.012763 d).

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[vsnet-chat 9317] MGAB-V240: standstill interrupted by fading (AM CVn?)
by Taichi Kato 20 Feb '23

20 Feb '23

MGAB-V240: standstill interrupted by fading (AM CVn?) Using ZTF data in 2022, I noticed that a standstill was interrupted by up to 2 mag short fading at least four times. The object became brighter (for a short time) after such events. The fading rates exceeded 1 mag/d in some cases and this object may be an AM CVn star. If this identification is correct, repeated regular outbursts before 2020 were superoutbursts (with a supercycle of about 10-15 d). Faint, but unusual object.

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